A substitutional quantum defect in WS$_2$ discovered by high-throughput computational screening and fabricated by site-selective STM manipulation

TL;DR

This study combines high-throughput computational screening and STM fabrication to identify and create a promising new quantum defect in WS$_2$, advancing quantum information applications.

Contribution

It introduces a systematic high-throughput computational approach to discover quantum defects and demonstrates their experimental realization via site-selective STM manipulation.

Findings

Identification of Co$_{ m S}^{0}$ as a promising quantum defect

Agreement between STM measurements and first-principles calculations

Demonstration of defect fabrication using STM techniques

Abstract

Point defects in two-dimensional materials are of key interest for quantum information science. However, the space of possible defects is immense, making the identification of high-performance quantum defects extremely challenging. Here, we perform high-throughput (HT) first-principles computational screening to search for promising quantum defects within WS$_2$, which present localized levels in the band gap that can lead to bright optical transitions in the visible or telecom regime. Our computed database spans more than 700 charged defects formed through substitution on the tungsten or sulfur site. We found that sulfur substitutions enable the most promising quantum defects. We computationally identify the neutral cobalt substitution to sulfur (Co$_{\rm S}^{0}$) as very promising and fabricate it with scanning tunneling microscopy (STM). The Co$_{\rm S}^{0}$ electronic structure measured by STM agrees with first principles and showcases an attractive new quantum defect. Our work shows how HT computational screening and novel defect synthesis routes can be combined to design new quantum defects.